Bug 16635: t/00-load.t warning from C4/Barcodes/hbyymmincr.pm

Bug 16635: t/00-load.t warning from C4/Barcodes/hbyymmincr.pm

According to http://perldoc.perl.org/vars.html, "our" should
be a reasonable substitute for the "use vars". By declaring as
"our", and removing the INIT, prove t/00-load will no longer
generate a warning about INIT for the C4/Barcodes/hbyymmincr.pm
module.

TEST PLAN
---------
1) prove t/00-load.t
   -- warnings about INIT for hbyymmincr
2) prove `git grep -l hbyymmincr | grep [.]t$`
   -- should all run okay
3) apply patch
4) repeat steps 1 and 2
   -- warning should be gone, and everything else run okay
5) run koha qa test tools

Signed-off-by: Srdjan <srdjan@catalyst.net.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit fd152d9e95a2236a00f3cb0284bdd2aa7cca6da2)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>